Braille embosser
The last stronghold of impact printing: a machine that presses dots up out of heavy paper instead of putting colour on it.
Solenoid-driven pins strike against a die plate so that the paper deforms permanently, which takes stock heavier than office paper — roughly 120–160 g/m², or the dot flattens out within a week of handling. A standard page holds about 25 lines of 40 cells, which is why a paperback becomes several heavy volumes. Double-sided embossing, called interpoint, offsets the dots on the reverse so they sit between those on the front rather than flattening them.
The text has to be translated first: braille has its own number signs and a system of contractions, work handled by software such as Duxbury or the open-source liblouis. The noise is dot matrix noise, often worse, which is why the machines are sold with acoustic hoods. The market is small and specialised — Sweden's Index Braille, outside Luleå, is one of the manufacturers — and the more expensive models also produce tactile graphics by varying dot density.